P物质与小鼠病毒性心肌炎机制研究

Role of substance P in viral myocarditis in mice

目的P物质广泛分布于中枢神经系统和外周组织如心脏内神经组织内,P物质在病毒性心肌炎病理生理中的作用尚不清楚,本实验研究P物质在小鼠病毒性心肌炎病理生理中的变化。方法脑心肌炎病毒(encephalomyocarditis virus,EMCV)接种4周龄DBA/2小鼠制成病毒性心肌炎模型。免疫组化法检测P物质阳性细胞在病毒性心肌炎小鼠心脏组织内的分布,酶免疫分析法测定P物质在病毒性心肌炎小鼠血清和心脏组织的水平。结果病毒性心肌炎小鼠心脏组织内P物质水平和P物质阳性细胞密度均低于正常对照组(P<0.05)。小鼠心脏组织P物质水平与小鼠心脏质量/体质量比值成负相关(r=-0.460,P<0.05)。小鼠血清与心脏组织P物质水平成正相关(r=0.399,P<0.05)。病毒性心肌炎小鼠血清P物质水平低于正常对照组(P<0.05)。结论病毒性心肌炎小鼠P物质血清水平降低,心脏组织内分布减少,可能反映心脏内神经组织受损,并引起心脏电活动调控和神经内分泌调节过程的改变。

Objective Substance P （SP） is widely expressed in the central nervous system and in peripheral tissues such as myocardial nerves. But the effect of SP in pathophysiology of encephalomyocarditis remains unclear. The purpose of this research is to study the SP changes induced by encephalomyocarditis virus （EMCV） in mouse viral myocarditis. Methods Four-week-old male DBA/2 mice were inoculated intraperitoneally with EMCV in phosphate buffered saline （PBS）. Localization of SP in the hearts was examined immunohistochemically, and concentration of SP in hearts and sera was measured by enzyme immunoassay. Results SP level and density of SP-positive cells in the heart of mouse inoculated with EMCV decreased as compared to those in normal controls （ P 〈 0.05 ）. There was a negative correlation between the heart SP levels and ratio of heart-weight to body-weight in the mice with EMCV infection （ r = - 0. 460, P 〈 0.05 ）. SP level was positively correlated with the ratio of heart weight and body weight （ r = 0. 399, P 〈 0.05 ）. Compared with the control group, SP level in serum was decreased in mice after EMCV inoculation. Conclusion SP levels in heart and serum decrease in viral myocarditis in mice, suggesting the damage of myocardial nerves may effect the myocardial electric activity and neuroendocrine process.